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2 Copy …Rights This slide set is the ownership of the 6DISS project via its partners The Powerpoint version of this material may be reused and modified only with written authorization Using part of this material must mention 6DISS courtesy PDF files are available from www.6diss.orgwww.6diss.org Looking for a contact ? Mail to : martin.potts@martel-consulting.ch Or bernard.tuy@renater.fr

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IPv6 Header The IPv6 header is designed To minimize header overhead and reduce the header process for most of the packets Less important information and option fields are moved to extension headers  IPv6 & IPv4 headers are not interoperable 7

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The Traffic Class field: used as in IPv4 Work done in diffserv wg (closed): RFCs 2474, 2475, 2597, 3260, … CU is Currently Unused (reserved) The Flow Label field: designed to enable classification of packets belonging to a specific flow A flow is a sequence of packets that should receive specific non-default handling from the network Intuitively: 5-tuple of the same source/destination address/port and transport protocol values Without the flow label the classifier must use transport next header value and port numbers  Less efficient (need to parse the option headers)  May be impossible (fragmentation or IPsec ESP) Further info:  RFC 3697 (PS) DSCPCU 6 bits 2 bits CoS support in IPv6 11

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Order is important (RFC 2460) IPv6 Hop by hop Destination Routing Fragmentation Authentication Security Destination Upper Layer Processed by every routerProcessed by routers listed in Routing extensionList of routers to cross Processed by the destination After reassembling the packet Cipher the content of the remaining information Processed only by the destination 13

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Conclusion Main changes in IPv6 protocol are within address format and datagram headers A lot of fields in the IPv6 header have disappeared  More efficient processing in the (intermediate) routers Optional extensions allow more functionalities (source routing, authentication, …) Optional header mechanism allows new options introduction without modifying the protocol 17